Wind deflector with actuating means for a slidable roof system

The wind deflector (10) is moved by the actuator (16) between an erect and a lowered position. The actuator consists of a memory alloy, e.g. NiTi-alloy, so that dependent upon its temperature, it can be in a first or a second condition. A current supply feeds heating current through the actuator. The actuator may consist of a wire, which has a first length in its first condition, and a second length in its second condition. An electronic control system regulates the temperature of the wire dependent upon the noise generated by the sliding roof, dependent upon vehicle speed, or dependent upon pressure variations in the vehicle.